1 /*
2  * Copyright (c) 2014 The Chromium OS Authors.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <environment.h>
10 #include <errno.h>
11 #include <fdtdec.h>
12 #include <os.h>
13 #include <serial.h>
14 #include <stdio_dev.h>
15 #include <watchdog.h>
16 #include <dm/lists.h>
17 #include <dm/device-internal.h>
18 
19 DECLARE_GLOBAL_DATA_PTR;
20 
21 /*
22  * Table with supported baudrates (defined in config_xyz.h)
23  */
24 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
25 
26 #ifndef CONFIG_SYS_MALLOC_F_LEN
27 #error "Serial is required before relocation - define CONFIG_SYS_MALLOC_F_LEN to make this work"
28 #endif
29 
30 static void serial_find_console_or_panic(void)
31 {
32 	const void *blob = gd->fdt_blob;
33 	struct udevice *dev;
34 	int node;
35 
36 	if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
37 		/* Check for a chosen console */
38 		node = fdtdec_get_chosen_node(blob, "stdout-path");
39 		if (node < 0) {
40 			const char *str, *p, *name;
41 
42 			/*
43 			 * Deal with things like
44 			 *	stdout-path = "serial0:115200n8";
45 			 *
46 			 * We need to look up the alias and then follow it to
47 			 * the correct node.
48 			 */
49 			str = fdtdec_get_chosen_prop(blob, "stdout-path");
50 			if (str) {
51 				p = strchr(str, ':');
52 				name = fdt_get_alias_namelen(blob, str,
53 						p ? p - str : strlen(str));
54 				if (name)
55 					node = fdt_path_offset(blob, name);
56 			}
57 		}
58 		if (node < 0)
59 			node = fdt_path_offset(blob, "console");
60 		if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node,
61 						    &dev)) {
62 			gd->cur_serial_dev = dev;
63 			return;
64 		}
65 
66 		/*
67 		 * If the console is not marked to be bound before relocation,
68 		 * bind it anyway.
69 		 */
70 		if (node > 0 &&
71 		    !lists_bind_fdt(gd->dm_root, blob, node, &dev)) {
72 			if (!device_probe(dev)) {
73 				gd->cur_serial_dev = dev;
74 				return;
75 			}
76 		}
77 	}
78 	if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
79 		/*
80 		 * Try to use CONFIG_CONS_INDEX if available (it is numbered
81 		 * from 1!).
82 		 *
83 		 * Failing that, get the device with sequence number 0, or in
84 		 * extremis just the first serial device we can find. But we
85 		 * insist on having a console (even if it is silent).
86 		 */
87 #ifdef CONFIG_CONS_INDEX
88 #define INDEX (CONFIG_CONS_INDEX - 1)
89 #else
90 #define INDEX 0
91 #endif
92 		if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
93 		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
94 		    (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
95 			gd->cur_serial_dev = dev;
96 			return;
97 		}
98 #undef INDEX
99 	}
100 
101 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
102 	panic_str("No serial driver found");
103 #endif
104 }
105 
106 /* Called prior to relocation */
107 int serial_init(void)
108 {
109 	serial_find_console_or_panic();
110 	gd->flags |= GD_FLG_SERIAL_READY;
111 
112 	return 0;
113 }
114 
115 /* Called after relocation */
116 void serial_initialize(void)
117 {
118 	serial_init();
119 }
120 
121 static void _serial_putc(struct udevice *dev, char ch)
122 {
123 	struct dm_serial_ops *ops = serial_get_ops(dev);
124 	int err;
125 
126 	if (ch == '\n')
127 		_serial_putc(dev, '\r');
128 
129 	do {
130 		err = ops->putc(dev, ch);
131 	} while (err == -EAGAIN);
132 }
133 
134 static void _serial_puts(struct udevice *dev, const char *str)
135 {
136 	while (*str)
137 		_serial_putc(dev, *str++);
138 }
139 
140 static int _serial_getc(struct udevice *dev)
141 {
142 	struct dm_serial_ops *ops = serial_get_ops(dev);
143 	int err;
144 
145 	do {
146 		err = ops->getc(dev);
147 		if (err == -EAGAIN)
148 			WATCHDOG_RESET();
149 	} while (err == -EAGAIN);
150 
151 	return err >= 0 ? err : 0;
152 }
153 
154 static int _serial_tstc(struct udevice *dev)
155 {
156 	struct dm_serial_ops *ops = serial_get_ops(dev);
157 
158 	if (ops->pending)
159 		return ops->pending(dev, true);
160 
161 	return 1;
162 }
163 
164 void serial_putc(char ch)
165 {
166 	if (gd->cur_serial_dev)
167 		_serial_putc(gd->cur_serial_dev, ch);
168 }
169 
170 void serial_puts(const char *str)
171 {
172 	if (gd->cur_serial_dev)
173 		_serial_puts(gd->cur_serial_dev, str);
174 }
175 
176 int serial_getc(void)
177 {
178 	if (!gd->cur_serial_dev)
179 		return 0;
180 
181 	return _serial_getc(gd->cur_serial_dev);
182 }
183 
184 int serial_tstc(void)
185 {
186 	if (!gd->cur_serial_dev)
187 		return 0;
188 
189 	return _serial_tstc(gd->cur_serial_dev);
190 }
191 
192 void serial_setbrg(void)
193 {
194 	struct dm_serial_ops *ops;
195 
196 	if (!gd->cur_serial_dev)
197 		return;
198 
199 	ops = serial_get_ops(gd->cur_serial_dev);
200 	if (ops->setbrg)
201 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
202 }
203 
204 void serial_stdio_init(void)
205 {
206 }
207 
208 #if defined(CONFIG_DM_STDIO) && CONFIG_IS_ENABLED(SERIAL_PRESENT)
209 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
210 {
211 	_serial_putc(sdev->priv, ch);
212 }
213 #endif
214 
215 void serial_stub_puts(struct stdio_dev *sdev, const char *str)
216 {
217 	_serial_puts(sdev->priv, str);
218 }
219 
220 int serial_stub_getc(struct stdio_dev *sdev)
221 {
222 	return _serial_getc(sdev->priv);
223 }
224 
225 int serial_stub_tstc(struct stdio_dev *sdev)
226 {
227 	return _serial_tstc(sdev->priv);
228 }
229 
230 /**
231  * on_baudrate() - Update the actual baudrate when the env var changes
232  *
233  * This will check for a valid baudrate and only apply it if valid.
234  */
235 static int on_baudrate(const char *name, const char *value, enum env_op op,
236 	int flags)
237 {
238 	int i;
239 	int baudrate;
240 
241 	switch (op) {
242 	case env_op_create:
243 	case env_op_overwrite:
244 		/*
245 		 * Switch to new baudrate if new baudrate is supported
246 		 */
247 		baudrate = simple_strtoul(value, NULL, 10);
248 
249 		/* Not actually changing */
250 		if (gd->baudrate == baudrate)
251 			return 0;
252 
253 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
254 			if (baudrate == baudrate_table[i])
255 				break;
256 		}
257 		if (i == ARRAY_SIZE(baudrate_table)) {
258 			if ((flags & H_FORCE) == 0)
259 				printf("## Baudrate %d bps not supported\n",
260 				       baudrate);
261 			return 1;
262 		}
263 		if ((flags & H_INTERACTIVE) != 0) {
264 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
265 			       baudrate);
266 			udelay(50000);
267 		}
268 
269 		gd->baudrate = baudrate;
270 
271 		serial_setbrg();
272 
273 		udelay(50000);
274 
275 		if ((flags & H_INTERACTIVE) != 0)
276 			while (1) {
277 				if (getc() == '\r')
278 					break;
279 			}
280 
281 		return 0;
282 	case env_op_delete:
283 		printf("## Baudrate may not be deleted\n");
284 		return 1;
285 	default:
286 		return 0;
287 	}
288 }
289 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
290 
291 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
292 static int serial_post_probe(struct udevice *dev)
293 {
294 	struct dm_serial_ops *ops = serial_get_ops(dev);
295 #ifdef CONFIG_DM_STDIO
296 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
297 	struct stdio_dev sdev;
298 #endif
299 	int ret;
300 
301 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
302 	if (ops->setbrg)
303 		ops->setbrg += gd->reloc_off;
304 	if (ops->getc)
305 		ops->getc += gd->reloc_off;
306 	if (ops->putc)
307 		ops->putc += gd->reloc_off;
308 	if (ops->pending)
309 		ops->pending += gd->reloc_off;
310 	if (ops->clear)
311 		ops->clear += gd->reloc_off;
312 #if CONFIG_POST & CONFIG_SYS_POST_UART
313 	if (ops->loop)
314 		ops->loop += gd->reloc_off
315 #endif
316 #endif
317 	/* Set the baud rate */
318 	if (ops->setbrg) {
319 		ret = ops->setbrg(dev, gd->baudrate);
320 		if (ret)
321 			return ret;
322 	}
323 
324 #ifdef CONFIG_DM_STDIO
325 	if (!(gd->flags & GD_FLG_RELOC))
326 		return 0;
327 	memset(&sdev, '\0', sizeof(sdev));
328 
329 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
330 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
331 	sdev.priv = dev;
332 	sdev.putc = serial_stub_putc;
333 	sdev.puts = serial_stub_puts;
334 	sdev.getc = serial_stub_getc;
335 	sdev.tstc = serial_stub_tstc;
336 	stdio_register_dev(&sdev, &upriv->sdev);
337 #endif
338 	return 0;
339 }
340 
341 static int serial_pre_remove(struct udevice *dev)
342 {
343 #ifdef CONFIG_SYS_STDIO_DEREGISTER
344 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
345 
346 	if (stdio_deregister_dev(upriv->sdev, 0))
347 		return -EPERM;
348 #endif
349 
350 	return 0;
351 }
352 
353 UCLASS_DRIVER(serial) = {
354 	.id		= UCLASS_SERIAL,
355 	.name		= "serial",
356 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
357 	.post_probe	= serial_post_probe,
358 	.pre_remove	= serial_pre_remove,
359 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
360 };
361 #endif
362